It's all go down at the Paper Aircraft Released Into Space (PARIS) headquarters ahead of our planned 23 October launch.
Earlier this week we wrapped the construction of the main payload box, which contains the vital Vulture 1 aircraft release mechanism, cameras, GPS tracker and radio beacon.
There's more on the successful …

Are you really sure about the

Are you really sure about the insulation? Seems to me your ascent time is likely to be so long as to defeat any insulation unless you've got a heat source inside the box... And if that's the case then adding a bunch of glass insulation, which is a very notorious clogger up of mechanical systems, might be a tad counter productive.

heater?

Since I suppose that weight is not really an issue in this box, I'd also suggest to add some sort of heater system. A battery and a resistor, or maybe some resistors, placed near the main components. At low temperature not only the batteries tend to malfunction, but electronics too. The exposed video camera can fail even if its batteries are kept warm. You should at least test it in the coldest environment you can find (industrial freezer cells?).

But ...

Oxygen?

Not enough oxygen available at critical altitude.

Chemical or electical solutions may be better. If you go electrical: LiPo batteries may have problems due to lack of external atmospheric pressure to keep the (vacuum-) pack together and working. Go LiIon with a cylindrical metal shell if you can. Make sure that the battery heats itself as well.

Not impressed with weight of box. Better get someone to sponsor you with low density Rohacell foam. Extremely good insulator as well. Glue it with epoxy or polyurethane and skip the duct tape. .

@Holtsmark

We're not talking those charcoal handwarmers, but the type which use an exothermic gel -- I've not seen any "in the flesh" as it were -- but they don't appear to have any air in them to cause expansion problems at altitude.

Re: Sorry

Now even more sorry

With the hindsight I should have warned of NSFW but I thought historic aircraft was exempt... After all it is displayed in front of thousands of visitors (including children) at every airshow at Duxford.

Silent treatment

release mechanism

By including the release mechanism within the payload box - that works on pressure differential - within a sealed box, aren't you in danger of altering the pressure around the release mechanism vs the actual exterior pressure, and hence it won't work as you intend?

A better solution to handwarmers?

What might be better are air-activated heatpacks with a perforated outer core. They look like big teabags and are frequently used in small animal and fish shipping. They can be taped to things which might be useful to prevent electronics freezing up. Just a thought.

condensation

condensation

Also you might want to put some desiccant (and/or a heating element of some sort) between the UV filter and the camera, it'd be a shame if all you got was pictures of ice crystals forming on the inside of the window.

What about orientedated?

Re: Hmm

Actually there is a word orientate - and it is theoretically more common in the UK whilst the version orient is more common in the US, and as Lester is in the UK...

The short version is slightly older in usage than the long version, as is often the case with Americanisms.

I already knew this - many of my colleagues wouldn't hesitate to agree to my 'Grammar-Nazi' credentials - but just to be sure, I also followed the principle of JFGI and found a source of info that wasn't the online encyclopaedia El Reg loves to hate!

Cold out != Warm in

I'm not convinced the extreme insulation to "keep the cold out" (as you put it) is likely to work. You also need to warm the interior. Other similar amateur balloon lift projects have used little chemical heat pads inside their styrofoam electronics containers, to keep the batteries warm. You can probably buy something useful at any drugstore, they're little chem packs, you break the interior vial so the catalyst mixes into the pack, and it stays warm for a few hours.